program main implicit none real*8, allocatable :: a(:), x(:,:) real*8 time integer*8 time0, time1, dtime integer i, j, n c n = 10000 c Initialization allocate(a(n), x(n,n)) do i=1,n a(i) = rand() end do c Start time call system_clock(time0) c Main calculation do i=1,n do j=1,n x(j,i) = cos(a(i)) * cos(a(j)) end do end do c Finish time call system_clock(time1, dtime) c Output time time = 1d0*(time1-time0)/dtime write(*,"(a7,f16.7)")"Time = ",time deallocate(a, x) end program